Boiler



arch 13, 1934. 'r. E. MURRAY 1,951,165

v BOILR Filed sept. 1o. 1927 `2 sheets-sheet 2 1N VEA/TOR water and steam from In anfzertain previous BOILER Thomas iE. Murray, Bradley Murray, .lohn IF. Murray, Murray, deceased,

Engineering Company,

York

Brooklyn, N. Y.; Joseph Thomas E. Murray, Jr., and executors of said Thomas E.

assignors to Metropolitan a corporation of New Application September lll, 1927, Serial No. 2l&,692 3 Glaims. (Cl. 122-235) application No. 642,725

iiled June 1, 1923, patented February 11, 1930,

Patent No. 1,746,711, having the sides of I have described a boiler the combustion chamber formed of or lined with water tubes so that they are exposed to the burning fuel.

directl radiant heat of the Boilers of this type have developed an extraordinary improvement in capacity and other advantages.

My present invention aims to secure similar advantages in connection with the overhead approximately horizontal The accompanying tubing. drawings illustrate embodiments of the invention.

Fig. l is a perspective view showing a boiler similar to that of my previous application, with my improvement applied to the overhead tubing;

Fig. 2 is a cross-section of the lower rowv of ordinary horizontal tubes and certain supplemental tubes;

Fig. 3 is a perspective view illustrating a modification. p

'I'he boiler of Fig. 1 is overhead tubes 1 heated by the passage of provided with the usual by convection, that is,

the gases between them.

Generally bailies are arranged to direct the course of thegases to utilize that heat to the to the steam drum over vertical headers 3 at the water descends to the head lfrom which the lower ends of such tubes.A

Below these tubes is a combustion chamber which is lined ,with vertical tubes 4 at the back and 5 at the sides and Gat thevfront. The hot these pass out through*A headers such as 7 at their upper ends, up to the drum, whence the water is returned to headers such as 3 at the bottoms of these tubes.

The fuel in the form of powdered coal, oil or gas is supplied in jets burns at a very bustion chamber so that illustrated are exposed heat. The lowermost .l0 is exposediin `the same way heat, and I propose to surface thus exposed.

Below the lowermost 10, I arrange ltubes so widely through nozzles 9 and high temperature in the comthe various water walls directly to the radiant row of horizontal tubes to the radiant increase the extent of regular bank of tubes one or more rows or banks of separated that they leale the tubes 10 partly exposed to the radiant heat,

" while theyfare themselves For example, in Figs. 2 and 3 are extended at fully exposed thereto. 1 and 2, thev headers their lower ends to` accommodate two supplemental rows of tubes 11 and 12 respectivelyat different levels. rlhe lowest row of tubes 12 are exposed to the rays from the burning gases throughout their entire circumference if we assume that combustion con` tinues up to the level of the lowest regular bank of tubes 10; or on considerably more than half their circumference even if we assume the combustion to be complete below these tubes 12 because the rays are not merely vertical but strike Jin' all directions -from the flame. i

Similarly the tubes 1l are exposed to the radiant heat over more than half their circumference, the full extent depending on the height to which the process of combustion continues. The tubes 10 are exposed, at the least, to such rays as can pass completely through the spaces left' between alternate tubes 1ly and 12 below. This means an exposure for the tubes 10 equal to approximately half their circumference. The greater the vertical distances between the banks of tubes 10, 11 and 12 respectively, the better the exposure of the banks above the tubes 12. The horizontal spacing of the supplementary tubes may be varied, but the maximum surface exposed to radiant heat is obtained by providing supplementary tubes invertical alignment with all the tubes 10 and at sufllcient vertical distances to secure very little interference with the rays projected from the re to the tubes 10. In Figs. l and 2, although I have referred to the tubes l0 and l1 as supplementary, yet they may be considered the ordinary overhead tubes modied only as to spacing. headers and the same circulating connections.

Fig. 3 shows an alternative construction in this respect. The lowermost bank of tubes l0 are connected to the lower ends of headers ld and 15 of the usual or any suitable type. Below these are two banks of supplemental tubes spaced in transverse section like the tubes l1 and l2 of Fig. 2. Corresponding tubes in Fig. 3 are numbered 16 and 11. At their upper ends both sets of tubes. are connected to a header 18 from which the hot water and steam pass by a pipe 19 to a drum, whence the water is returned by an outside circulatingpipe to ends of the tubes 16 and `17.

The tubes which surround the combustion chamber are sh n bare. The invention may be applied, howev to installations in which such tubes are shielded to a greater or less extent. In eitherv case there is a utilization of the intense radiant heat of the burning fuel, more effective than the heating of the upper tubes by contact the drum 20 at the lower.

or convection gases, and there is 'also a great diminution in cost of installation and maintenance compared with the ordinary refractory walls.

Various other modifications may be made by those skilled in the art without departing from the invention as dened in the following claims.

What claim is:

l. A boiler having above the combustion chamber a bank of approximately horizontal tubes below which and approximately parallel thereto is a second bank in a plurality of horizontal lines of staggered tubes, the tubes of both banks being of the same diameter, the tubes in horizontal alignment in the second bank being spaced apart farther than those in horizontal alignment in the first bank, and the vertical distance between the tubes in adjacent horizontal lines of the second bank being greater than that between the horizontal lines of tubes in the rst bank.

2.. A boiler having above the combustion chamber abank of approximately hor ontal tubes below which and approximately arallel thereto ls a second bank, the space between the two banks ef tubes being ,unobstructed and the tubes of the second bank being spaced farther apart than those of the rst bank and being so widely separated as to expose the tubes of the rst bank to the radiant heat of the burning fuel in the combustion chamber below, means for burning fuel in suspension in the combustion chamber and a set of upright steam generating tubes lining said combustion chamber and having a circulating system which is independent of that of the overy head banks.

3. Aboiler having above the combustion chamber a bank of approximately horizontal tubes below which and approximately parallel thereto is a second bank, the tubes of the second bank being spaced farther apart than those of the rst bank and being so widely separated as to expose the tubes of the rst bank to the radiant heat of the burning fuel in the combustion chamber below,

headers carrying the rst bank of tubes and separate headers carrying the second bank and providing an independent circulation therefor,

means for burning fuel in suspension in the combustion chamber and a set of upright steam generating tubes lining said combustion chamber and having a. circulating system which is independent of the circulating systems of the two overhead banks.

Y THOMAS E. MURRAY.- 

